The present invention relates to an arrangement for dosing, particularly caking fuels, in a fluidized bed reactor, in which an injection pipe for fuel supply is provided with an injection nozzle in the fluidized bed reactor and surrounded by a jacket pipe for a fluid supply (jacket fluid) provided with a jacket nozzle at its end. The invention also relates to a method of dosing fuels into a fluidized bed reactor.
Fluidized bed reactors are widely utilized in the field of utilization of fuels, and the fuels can be solids, liquids or gaseous. In such processes, combustion, degasification or liquefaction of fuels can take place. The fluidized bed reactor for these processes operates as a rule with a fluidized bed of an inert material, and the fuel to be treated is supplied in the reactor as continuously as possible, and the residues are sluiced out of the reactor. An injection supply is used in these cases as a suitable dosing technique. The fuel is conveyed through an injection pipe ending in the fluidized bed reactor with a suitable fluid, whereas so-called jacket fluid flows through a jacket pipe surrounding the injection pipe and enters at the same location at which the fuel through a jacket nozzle into the fluidized bed reactor. The jacket fluid cools the injection pipe and prevents starting of the fuel reaction prior to fuel entry into the fluidized bed. Moreover, the jacket fluid provides for good mixing of the fuel with the material available in the fluidized bed. It has been recognized that the above described injection supply device leads to practical results only conditionally, inasmuch as, first of all, in the event of fuels having a tendency to caking, such as for example some types of coal, the cooling with the jacket fluid must be so intensive that it unfavorably affects the temperature distribution in the fluidized bed. Otherwise there is a latent danger of clogging in the region of the dosing device.